An Ok Singly-Linked Stack

In the previous chapter we wrote up a minimum viable singly-linked stack. However there's a few design decisions that make it kind of sucky. Let's make it less sucky. In doing so, we will:

• Deinvent the wheel
• Make our list able to handle any element type
• Add peeking
• Make our list iterable

And in the process we'll learn about

• Advanced Option use
• Generics
• Lifetimes
• Iterators

Let's add a new file called second.rs:

// in lib.rs

pub mod first;
pub mod second;

And copy everything from first.rs into it.